Mixing tube for gas burners



1954 L. c. SASSMANHAUSEN ,69

MIXING TUBE FOR GAS BURNERS Filed June 8, 1949 2 Sheets-Sheet l O \I Q (D {T W L? 1 N V EN TOR. L ee C. JQSSmQnhQL/Sen Afforneus.

1954 L. c. SASSMANHAUSEN MIXING TUBE FOR GAS BURNERS 2 Sheets-Sheet 2 Filed June 8, 1949 INVENTOR. Lee C. sqssman/qausefl gm. f

Attorneys- United States Patent Qfiice 2,694,445 Patented Nov. 16, 1954 MIXING TUBE FOR GAS BURNERS Lee C. Sassmanhausen, St. Clair Shores, Mich.

Application June 8, 1949, Serial No. 97,836

3 Claims. (Cl. 158-118) This invention relates to a gas burner and it has to do particularly with a gas burner for space heating purposes.

The gas burner structure of the present invention is admirably adapted as a conversion burner in the sense that it may be installed in a furnace which, previous thereto, was arranged to consume a different type of fuel, such as coal or oil, or the burner of the present invention may be used as a replacement for another gas burner. On the other hand, the burner of the present invention, and particularly some of the features thereof, may be employed with original equipment.

The general objects of the invention are to provide a simplified light weight burner and burner structure which can be manufactured economically so that the retail cost thereof may be reflected in the price to the ultimate purchaser and user. Due to its light weight it may be easily and economically transported. In connection with the weight of the structure, it may be pointed out that heavy metal castings are very largely dispensed with and in place thereof parts are fabricated from sheet metal with some parts of tubular form.

A furnace structure made in accordance with the invention is shown in the accompanying drawings:

Fig. 1 is a side elevational view of a burner constructed in accordance with the invention showing the same mounted in a furnace with some of the furnace structure shown in broken lines.

Fig. 2 is an enlarged cross sectional view showing the structure of the mixing tube and the air control openings.

Fig. 3 is an end view showing the gas conduit in section.

Fig. 4 is a side elevational view showing an air control sleeve.

The support for the burner advantageously comprises a member 1, and a cross piece 2, provided with floor engaging screw threaded studs 3 which are threaded into the cross support and the inner end 5 of the member 1 and which may be locked in position by nuts 4.

As shown in Fig. l, a portion of a furnace is illustrated at 8 and the support is disposed to lie partially within an area 9 within the furnace. This is the lower part of the furnace and if the furnace previously used coal, the area 9 could have been the ash pit. The former grate level of the furnace is indicated at about the broken line 10 while the combustion chamber is illustrated at 11. The compartment 9 is to be closed and this may be done by two sheet metal members 13 and 14 secured together in their central portion by screws 15.

The mixing tube and air control portions of the burner are shown in detail in Fig. 2. There is an outer tube of sheet metal provided with a set of apertures 21 which are circumferentially spaced and a set of apertures 22. Slidably mounted on the tube 20 is a sleeve 23 for controlling the apertures 22 which serve as inlets for primary air, and a sleeve 24 which controls the apertures 21 for secondary air. The sleeve 24 is mounted on the tube 20, as shown in Fig. 4, as by means of a set screw positioned in an elongated slot 25. It will be readily appreciated how, by loosening the screw, the sleeve 24 may be axially adjusted and then held in position by tightening the screw. The sleeve has a scalloped or notched edge, the notches being shown at 26 to better obtain a fine adjustment of the throttling of the apertures 21. In this way, instead of providing a small crack for a small opening, separate openings at the notches 26 are provided which have suflicient cross sectional areas for the passage of air therethrough with a minimum of tendency to collect or trap lint or dust. The sleeve 23 is similarly adjusted and set by a screw 27.

There is a closure for one end of the tube 20 in the form of a sheet metal cup or disc 30 and a hub or bushing 31 receives the jet or orifice member of the gas supply pipe. This gas jet member is shown at 32 and it may be held in position by a set screw 34.

The venturi or mixing tube comprises a partially cone shaped or funnel shaped element 36, the outer peripheral edge of which may be welded to the inside of the tube 20 and this is connected, as by means of welding, to a tapered mixing tube 37. The mixing tube 37 is of tapering form from its end which connects to the inlet element 36, to about the point 38, and from the point 38 to its opposite end the portion, as shown at 39, is preferably cylindrical. Positioned over the portion 39, and a part of the portion 37, is a tubular element 40, which preferably has some considerable axial extent and which has its inner end turned inwardly, as at 41, and secured to the mixing tube 37. The parts just described are all of sheet metal structure and indeed some of them may be made from steel tube. For instance, the element 20 may be fashioned from steel tube; the mixing tube 37 may be fashioned from steel tube swedged into its tapered form and the element 40 may be of steel tube.

The element 40 is designed to telescopingly receive the main burner tube 45. The fact that the member 40 has considerable axial extent provides for a good strong engagement and it might be pointed out that the element 40 is provided with a longitudinal split where its edges are spaced apart as shown at 47 so that the element 40 may be slightly contracted by the burner tube to provide a tight engagement. The burner tube 45 is somewhat of L shape so that its free end extends upwardly, as shown in Fig. 1. The burner tube supports a bafiie or deflector 50 preferably in the form of a pan shaped stamping of heat resisting metal, such as one of the stainless steels. A post or rod supports the deflector and the post is secured to the burner tube by means of a member 52.

The described mixer tube, venturi and burner tube assembly is mounted on the support for which purpose the body member of the support is provided with a number of U shaped brackets each shown at 60, and a series of clamps 61 (Fig. l) are engaged around the exterior tubular form and are passed through the U shaped brackets and tightened each by a screw (not shown). The two clamps 61 disposed within the furnace chamber 9 engage the tube 45 while the exterior clamp 61 engages the outer tube 20 and is of slightly larger size. The structure is disposed as shown in Fig. l, with the tube 20 and the frame member 1 passing through the enclosing plates 13 and 14 with the parts so positioned that the secondary air apertures 21 are disposed just outside the closure plates 13 and 14.

The operation is as follows: The fuel gas, of course, is projected in the form of a jet from the jet 32 into the venturi constituted by elements 36 and 37. The venturi action causes a draft of air to enter the primary air ports 22 which, as above explained, can be regulated by the sleeve 23, so that the proper combustible mixture of gas and air is obtained in the venturi. This mixture passes into the tube 45 and upwardly Where the flame burns at the upper and outlet end of the pipe 45. The fl me thus burning upwardly strikes the diverter or bafiie 50 and is spread outwardly in all directions in the fire box or fire chamber 11. Of course, suitable controls may be used for automatically governing the inlet of the gas but the controls constitute a separate art. Secondary air is supplied to the flame through the control ports 21 located just outside the plates 13 and 14 and regulated by the sleeve 24. This secondary air flows through the circumferential space 42 between the outer tubular member 20 and/or the tube 45 and tube 39, depending upon the adjustment of the tube 45. It will be appreciated that this telescoping adjustment is capable of accommodating furnaces of different sizes and,

while in Figs. 1 and 2, the tube 45 is telescoped well over the member 40, it may, in some instances, be shifted to the right, as Fig. 7 is viewed. The secondary air passes into the furnace chamber 9 and then upwardly by the convection currents.

The pilot burner and its support are carried by a bar or strip of metal, as at 70, with its inner end mounted on the tube 45 as by means of a clamp 71 and the extreme inner end is folded back upon itself to provide a hook 72. The intermediate portion of this bar is inclined as at 73 and the portion of the track which extends out through the plates 13 and 14 is preferably horizontally disposed and is supported by a bracket 74 carried by the support member 1.

The support has a part 81 for engaging the track 70, that is notched to engage the hook 72. The pilot burner is shown at 85 and from the burner a pilot flame as at 86 burns.

I claim:

1. A gas burner structure substantially as described comprising, an outer sheet metal tubular member, means for discharging a jet of gas into the said tubular member, a mixing tube of sheet metal within the outer tubular member having a flared inlet positioned to receive a jet of gas and a tubular body portion spaced from the inner wall surfaces of the outer tubular member, the outer tubular member having one or more openings therein adjacent the inlet end of the mixing tube for the passage of primary air into the mixing tube, the outer tubular member having other openings positioned downstream from the inlet end of the mixing tube for the passage of secondary air therethrough and through the space between the outer tubular member and the mixing tube, a split metal sleeve of spring characteristic mounted on the inner end of the mixing tube and a burner tube arranged to frictionally telescope in slidably adjustable manner over said split sleeve.

2. A gas burner structure comprising, an outer tubular member of sheet metal construction and substantially of uniform diameter from end to end, a mixing tube of sheet metal construction, tapered toward its inlet end and disposed within the outer tubular member with a space between the outer tubular member and the mixing tube, the mixing tube having a flared inlet the extreme end of which fits against the inner surfaces of the outer tubular member, the outer tubular member extending beyond the inlet end of the mixing tube, gas supply means for projecting a stream of gas into the tapered inlet of the mixing tube, the outer tubular member having openings in its wall upstream from the inlet end of the mixing tube for the entrance of primary air therethrough and into the inlet end of the mixing tube, the outer tube having apertures therein downstream from the inlet end of the mixing tube for the entrance of secondary air therethrough and into the space between the outer tubular member and the mixing tube, means on the outer tube for regulating the said openings therein 4 for controlling both the entrance of primary air and secondary air, a split sleeve having yielding characteristics mounted on the mixing tube adjacent its downstream end, and a burner tube adapted to be slidably fitted over said split sleeve for relative axial adjustment and to project into the outer tubular member with clearance between the burner tube and the outer tubular member for the passage of the secondary air therethrough, the outer tubular member adapted to be passed through a wall of a furnace or the like with the openings therein disposed outside of said wall, the burner tube and the mixing tube being axially adjustable whereby to adjust the structure to the size and dimensions of the furnace. 3. A gas burning structure for use with a furnace which has a wall, comprising an outer tubular member adapted to pass through the wall, a mixing tube within the outer tubular member having a flared inlet, a device for projecting gas into said inlet, the outer tubular member extending outwardly beyond the flared inlet and having openings in its walls positioned adjacent its outer end and outwardly beyond the flared inlet to permit the passage of primary air into the mixing tube, the mixing tube being spaced from the interior surfaces of the outer tubular member, the outer tubular member having openings positioned downstream from the flared inlet for the passage of secondary air therethrough and into the space between the outer tubular member and the mixing tube, characterized by; the said openings for admitting primary air and the said openings for admitting secondary air being adapted to be positioned outside of the furnace wall, adjustable means being provided for regulating the size of the said openings, said means being adapted for disposition outside of the furnace wall, and a burner tube connected to the mixing tube for the discharge of combustible gaseous mixture to support a flame, said burner tube being adapted for dispostion within the burner wall and being adjustably connected to the mixing tube.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 391,537 Kloeb Oct. 23, 1888 1,165,835 Birkholz Dec. 28, 19l5 1,350,226 Igou May 18, 1920 1,572,833 Baker Feb. 9, 1926 1,731,306 Hileman Oct. 15, 1929 1,994,547 Urquhart Mar. 19, 1935 2,178,703 Robbins Nov. 7, 1939 2,241,583 Campbell May 13, 1941 2,260,167 Cope Oct. 21, 1941 2,461,913 Mosier Feb. 15, 1949 FOREIGN PATENTS Number Country Date 43,019 France Nov. 7, 1933 

